AS 1657—2013 Clause 4.5

[sdz]

4.5 SAFETY BELOW THE PLATFORM OR LANDING
Where persons have access to or work beneath any platform or landing, the floor of such platform or landing shall be designed, or provided with protection, to prevent objects falling through the floor reaching the area below.
NOTE: Protection may typically take the form of a lightweight protective barrier fixed beneath the platform, walkway or landing (e.g. 12 mm square mesh).
No aperture in the protection shall permit the passage of a 15 mm diameter ball.

I am designing an outdoor raised equipment platform about 3m high. This is in a compound with no public access and will occasionally have maintenance personnel working on and sometimes under the platform. Can I use grating with openings over 15mm in this case?

 

[IDS]

If there is a recognised hazard that can be removed or reduced by a measure that is "reasonably practicable", then you are required to do it.

So the answer is no.

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[BJI]

Can't say I have ever seen this implemented, for occasional maintenance temporary mesh sheets can be placed over the grating to prevent items falling, this is pretty common practice. If it was normal operation that required access below then maybe finer load bar spacing or a secondary mesh barrier would be justified.

 

[Arches_Pillars]

The use of "shall" makes it mandatory.

The clause is also referred in Clause 3.2.3.4 where use of expanded mesh with an appreture not exceeding 45mm is allowed by the Standard as shown in Figure 3.1
However, trafficable areas below this expanded mesh must comply with Clause 4.5.
This means a lightweight mesh is to be placed under the expanded mesh to protect people passing under it.

Platforms and walkways in refineries are one on top of the other.
Stair towers got landings one on top of the other too.
Most of them do not comply with this clause which is a worry.
This clause should be revised.

 

[sdz]

In mining process plants it's not done but there everyone is supposed to be wearing a hard hat. A lightweight mesh under the grating would just catch material and make cleaning difficult, promoting corrosion.

 

[human909]

We our platforms to suit this requirement. But it does seem that not many other people are doing so.

Webmesh or similar is the grating product that meets Clause 4.5.

https://www.webforge.com.au/webforge/access/ancillaries/webplate-webmesh

The clause is pretty clear cut. Excuses such as wearing a hard hat doesn't magically exempt you.

"Where persons have access to or work beneath any platform or landing, the floor of such platform or landing shall be designed, or provided with protection, to prevent objects falling through the floor reaching the area below."

Though I agree the provision is onerous.

 

[IDS]

Though I agree the provision is onerous.

Why is it onerous?

Since legislation requires that risks and hazards be removed or reduced so far as is reasonably practicable, and since providing a finer mesh appears to be reasonably practicable, it would seem that the code requirements are consistent with legal safe design requirements.

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[BJI]

Technically there is no legal requirement to follow AS 1657, it is only guidance, unless it is adopted by legislation or in purchaser contracts. It may be good practice to follow regardless, and if something did happen then it may be hard to justify why you chose to deviate from this guidance.

 

[IDS]

Technically there is no legal requirement to follow AS 1657, it is only guidance, unless it is adopted by legislation or in purchaser contracts.

The safe design legislation does not refer to specific standards, but it does require that "risks and hazards be removed or reduced so far as is reasonably practicable", and it would be difficult to argue that something required by an Australian Standard was not "reasonably practicable".

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[BJI]

Some OS&H legislation do refer to specific standards. The national work health and safety codes of practice also refer to AS 1657 but always uses 'should' terminology to follow the guidance. There could be other ways to mitigate the risks, ultimately it is up to the end user to mandate what they want, if they don't adopt these guidelines. This is not a new clause in the standard, it was in the 1992 version as well (and probably the previous), although they did remove the frequent basis part. I have never seen it implemented on an industrial or mining structure. I have seen temporary sheeting used to prevent objects falling during TA, when maintenance is being performed and there is an increased risk of falling objects from platforms, this is at least RAGAGEP.

 

[IDS]

What is "RAGAGEP"?

What is the advantage of using temporary sheeting, rather than using a finer mesh that complies with the code?

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[BJI]

RAGAGEP = Recognised And Generally Accepted Good Engineering Practices

 

[human909]

Why is it onerous?

Since legislation requires that risks and hazards be removed or reduced so far as is reasonably practicable, and since providing a finer mesh appears to be reasonably practicable, it would seem that the code requirements are consistent with legal safe design requirements.

Because it is more expensive and to install and maintain and usually provides limited reduction in risk. In my view it isn't 'reasonably' practicable. Your same argument could be used to fully enclose a walkway in mesh to prevent objects going over the sides.

What is the advantage of using temporary sheeting, rather than using a finer mesh that complies with the code?

The use of mesh isn't cheap to install or maintain and may increase risks as cleaning is not 'reasonably practicable'. Safety is always a balance between what is reasonable. And we always accept some degree of risk even if our laws and codes don't always recognise this.


A much more sensible approach is to consider how frequently the walkway above and the area below is trafficked and the consequences of a 15mm sized object hitting somebody. You know, a proper risk assessment rather than a one size fits all approach.

 

[Arches_Pillars]

AS 1657 covers both commercial and industrial industries. Commentary should expound on clause 4.5.
There is a huge disparity on risks to dropped objects between
(a) a person walking to work in the central business district (CBD) where construction is in progress and
(b) a person walking inside a mining facilty where he is inducted and made aware of how his behaviour can impact on his safety and others' safety

Perforated scaffold planks like these(link below) are installed on both (a) and (b) above as needed - not a permanent fixture everywhere in a gas refinery or mining facility.
This plank will pass the apperture requirement of Clause 4.5.
Metal Steel Scaffold Planks Suspended Aluminum Perforated Metal ...

https://images.app.goo.gl/9koJ5ygzxbe6vFC99

The mandatory "shall" compels the engineer to adapt this mesh or design an equivalent on "all" platforms situated over "trafficable areas."

On (a) above, it is mandatory and common practice adapt this.
On (b) above, it should be mandatory on conveyor walkways or similar parts of the plant where material drops on a consistent basis and where people need to walk under particulary where it is defined as a local thoroughfare locally.